Study Casts Doubt on New World's First SettlersNew evidence undercuts long-held beliefs about early inhabitants of North America. Evidence of the Clovis culture, discovered in 1952 in New Mexico, suggested a migration from Asia at the end of the last Ice Age. A new report points to a later arrival.

A lively controversy over the identity of the first Americans has taken another turn. New research finds that a culture that appeared at the end of the last ice age arrived in North America later than had been thought and existed for only a short while.

The authors of this new study argue that what's known as the Clovis culture was not the first in the Americas, as is often thought. NPR's Richard Harris reports.

RICHARD HARRIS: The traditional story about how people came to America is that these first settlers came across a land bridge from Russia, around the end of the last Ice Age. They walked down a gap between glaciers into the present day United States and they hunted down wooly mammoths and mastodons.

Michael Waters at Texas A&M University says it's long been assumed that these first inhabitants are responsible for the characteristic spearheads and other tools that archeologists call the Clovis culture.

Mr. MICHAEL WATERS (Anthropology and Geography, Texas A&M University): For over 50 years, our ideas about the first Americans have been overshadowed by a concept known as the Clovis first model. It was thought that these were the first people to enter the New World, and that Clovis and their descendants then spread out across North America and reached the southern tip of South America within about a thousand years after that.

HARRIS: To check this story, Waters and a colleague, Thomas Stafford, decided to reexamine Clovis materials using new and improved dating methods. They wanted to know more precisely the age of Clovis sites, which are scattered across North America all the way to Florida. The results are in today's issue of Science Magazine.

Mr. WATERS: Lo and behold, when we did this, we found that we could revise the age of Clovis that wasn't quite as old as previously thought.

HARRIS: The earliest signs of Clovis technology date back a little more than 13,000 years ago. And he says, the culture was around for much less time than commonly thought.

Mr. WATERS: Clovis only lasted for about 200 years or 20 generations. And so the consequences creates a lot of problems for the Clovis first model.

HARRIS: Most notably, the new date suggests that Clovis might not have come first. Archeologists have dated non-Clovis sites from Canada to South America, and some of those now appear to be older than the ones that Waters has now dated. So he suspects the simple story of a single culture migrating into the Americas is wrong. His hunch is that there were multiple migrations from Asia, both by land and sea.

Mr. WATERS: Both routes are viable and possible. And we have to start thinking about the people like, the Americas being such that people could have arrived at different times and they could have arrived by different ways. The data that we collected, you know, is probably the final nail in the Clovis first coffin.

Mr. GARY HANES(ph) (University of Nevada, Reno): I would have to say that's a bit of an overstatement.

HARRIS: Gary Hanes is at the University of Nevada, Reno. He says he's impressed by the careful new dates that Waters and Stafford have published describing the Clovis sites.

Mr. HANES: But at the same time, they haven't done that to the dates of the things - the other sites, the other technology - that they compare it to. So they've given us a good, clear picture of Clovis but we're still left with this fuzzy picture of all the other stuff they say existed at the time of Clovis but we don't know that for certain.

HARRIS: Maybe the shadowy figures who date back to around the time of Clovis will prove to be younger too, he says. Happily, this is one dispute that can be resolved fairly easily with yet more precise dates of these archeological sites.

Michael Waters at Texas A&M knows he has a few more archeologists to convince and he'll keep at it.

Mr. WATERS: This could have been very exciting to chase after this problem of the people in Americas and I'm confident that we'll eventually come up with a coherent model that makes sense, and we'll tell the story.

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